Recent Tabs

Recent Tabs feature keeps track of currently opened documents. SSMSBoost remembers document names and their connections. If documents are new and were not saved (Query1.sql)
they will be still remembered and unsaved content will be saved, coupled with
SQL Editor Contents History feature.
You can use these feature by using one of commands:

Restore last closed tab simply restoring last close tab, including it's connection without any further questions

Pick recent tab shows Recent Tabs dialog, allowing you to choose one of the Tabs from the history:
"Freeze" option allows you to force persistence of the tab in the recent tabs, until you manually delete it.

Make sure you check SSMSBoost Settings->Recent Tabs for fine-tuning options.